All of Lyndsy Fonseca and David Henrie's scenes as Ted's future children were filmed during the first season to keep them the same age throughout the series. This includes a scene for the show's eventual final episode that includes the titular Mother which were filmed early in the second season.
Three of the main actors on the show have had their significant others in multiple episodes. Husband of Alyson Hannigan, Alexis Denisof, plays Sandy Rivers; Cobie Smulders husband Taran Killam, plays Blauman; and David Burtka, husband of Neil Patrick Harris, plays Scooter.
After the show ended, Josh Radnor kept the blue french horn, Neil Patrick Harris got the Playbook and the gang's MacLaren's booth, and the three yellow umbrellas now belong to director Pamela Fryman, as well as creators Craig Thomas and Carter Bays.
The clock in Marshall and Teds apartment is always set at 4:20. Except for episode 7.2, it is set to 14.10
There are only 18 times throughout the entire series that Barney shows up without a suit.
Jim Parsons, who stars in The Big Bang Theory, auditioned for the role of Barney Stinson.
Most of the websites featured in the show such as canadiansexacts.org, stinsonbreastreduction.com, extremitiesquarterly.com and balloonexplorersclub.com are real websites. lilyandmarshallselltheirstuff.com was created for charity and items from the show were auctioned off.
Due to Jason Segel's (Marshall) real-life smoking habit, he and his co-star and on-screen wife, Alyson Hannigan (Lily), rarely kissed on-screen during the run of the show; kisses between the two were infrequently scripted, at Hannigan's request, because she disliked the taste and smell of smoke on Segel's breath.
The episode, "The Pineapple Incident," in Season 1, is the most viewed episode of HIMYM.
Five books that are related to the show have been published. This includes the now famous, "The Bro Code" and, "The Playbook".
Barney is truly the inventor of "The Bro Code" (the rules which he feels a man must follow in order to be considered a "bro"). According to the number of Google searches, the phrase was non-existent until 2008.
Many episodes deal with Robin's past as the teen pop star Robin Sparkles, including her big hit "Let's Go to the Mall." That song is available on the dancing game "Just Dance 3".
Jason Segel, whose character Marshall on How I Met Your Mother brags about once winning a high school slam dunk contest, really DID win a high school slam dunk contest.
In the DVD commentary for the Pilot episode, Josh Radnor reveals that he is allergic to dogs, something the creators didn't know until Radnor was cast. That may have played a part in the decision to get rid of Robin's dogs in Season 2, when she and Radnor's characters are dating.
When promoting the final season on The Talk (2010), Alyson Hannigan was unable to answer what she would miss the most about Jason Segel. She became teary as it was too emotional a topic for her.
Whenever two characters get in a physical altercation, the song 'Murder Train' by Robin's ex-boyfriend Simon's band 'The Foreskins' is heard under the scene.
In an online poll, Victoria (Ashley Williams) was voted the all time favorite love interest of Ted (Josh Radnor) on the show. Jeanette was voted the least favorite. Zoey made it on both lists.
In Season 7, one can see Conan O'Brien in the background at the gang's famous McLaren's Pub.
In an episode where Barney is challenged to pick up a girl in a bar by calling an ambulance, Carter Bays and Craig Thomas, the creators of the show can be seen as the actors playing the paramedics.
Because of the numerous scenes and the quick-cut nature of the show's visual style, the show is filmed without the traditional live studio audience. The finished episode is later shown to an audience, and their reactions are recorded and added for broadcast. The series' creators joke that the long set-up time between scenes would cross the line from "studio audience" to "hostage situation."
In most "statistics" Barney Stinson expresses, the numbers 83 or 8 and 3 are involved. And in one instance, when he posed as an elderly man, he claimed his age was 83. In another, Barney wants to get in bed with a woman from a magazine, and her picture appears on page 83.
In season 4 when referring to the child he hired to act as his son, Barney makes a comment how child actors were better in the 80's. Neil Patrick Harris who plays Barney was himself a child actor in the 80s.
Ted and his friends regularly go to MacLaren's Pub, which is a bar right below Ted's apartment. The pub was named after 'Carl MacLaren', who is the associate producer, assistant to Carter Bays. Also, a bartender named Carl plays a minor role in the show.
Barney Stinson was named after a heroin peddler in the James Ellroy book 'LA Confidential'.
Although singers Britney Spears and Katy Perry were two of the biggest guest stars, fashion designer Tim Gunn was the most welcomed guest star from the cast and crew. Nearly everyone on set wanted an autograph from him.
Each character in the series has had their own musical number except Lily. Ted had his own musical number called "Super Date" in the episode "Of Course" (2010) Barney has his own musical number called "Nothing Suits Me Like a Suit" in the episode "Girls vs. Suits" (2010) Robin had her own musical number (and many others) called "Lets Go To The Mall" in the episode "Slap Bet" (2006) and Marshall has his own musical number called "Marshall vs. the Machines" (2010) and that leaves Lily without ever having her own musical number. This is down to actress Alyson Hannigans (Lily) dislike of singing.
Alyson Hannigan was pregnant while filming many season four episodes, but the show-runners were not interested in her character, Lily, also being shown as pregnant. Most episodes used time-honored TV tricks to hide Hannigan's pregnancy, including baggy tops and giant handbags, but the episode "The Possimpible" showed Hannigan's pregnancy bump in the context of a subplot in which Lily wins a hot dog-eating contest and has a comically distended stomach afterward. A similar visual gag was used in the sitcom Titus (2000) several years earlier. Actress Cynthia Watros was pregnant during the show's second season, although her character "Erin" was not meant to be pregnant. So, in addition to the "time-honored TV tricks" being used to hide Watros' pregnancy, a flashback scenario was used in one episode that showed her character Erin winning a pie-eating contest and her actual pregnant belly was shown afterwards. After Hannigan told the show-runners that she was pregnant, Cobie Smulders discovered that she was also pregnant. Neither of the characters they play were pregnant on the show, so the costumers had the job of simultaneously hiding the pregnancies of the series' two main female actors.
In this show Ted, Lily and Marshall are of the same age, but in real life Josh Radnor and Alyson Hannigan are 6 years older than Jason Segel.
Cobie Smulders is from Vancouver. Her character, Robin Scherbatsky, was originally supposed to be from Toronto, but this was changed to make her also from Vancouver.
Writers/producers/co-creators Carter Bays and Craig Thomas are members of the band "The Solids," who perform the show's theme song "Hey Beautiful". The Solids' first performance was at Wesleyan University, which is the alma mater of both Bays and Thomas, as well as of the characters Ted, Marshall, and Lily.
Alicia Silverstone was originally cast as Stella Zinman but dropped out of the role. Reports at the time indicated that upon learning that Britney Spears would be playing her receptionist Abby, Silverstone's reps had her withdraw from the role because they did not want her first appearance on the series to be overshadowed by Spears.
Barney has had both a clone trooper and a storm trooper costume in his apartment throughout the series.
Bob Saget narrated 206 episodes of HIMYM, but didn't narrate the last two. The last two episodes were narrated by Josh Radnor.
If one were to discount Robin (Cobie Smulders), since she is a main character, then the ex-girlfriend of Ted's (Josh Radnor) who has appeared in the most episodes would be Victoria (Ashley Williams), with 16 overall.
Anne Dudek, who plays the girl whom Ted breaks up with repeatedly on her birthday, also played Precious on an episode of Friends. Precious is the ex-girlfriend of Mike (Paul Rudd) who he has to break up with upon returning from Barbados in Season 10, Episode 1. The day of the break-up turns out to be her birthday.
Before co-starring in the show, Josh Radnor and Neil Patrick Harris appeared in a stage production of John Robin Baitz' play "The Paris Letter" in 2004, in which they played lovers, each walking onto the stage fully nude.
Famous for his suits in this series, Barney has suits for every occasion, including flight suit for Halloween and suitjamas for sleeping in.
When Ted meets Klaus, Victoria's German fiancé, they speak a few words in German. One term Klaus uses is "Lebenslanger Schicksalsschatz", which translates into "lifelong treasure of destiny". While the words "lebenslang" (lifelong), "Schicksal" (destiny) and "Schatz" (treasure) are real German words, the term "Lebenslanger Schicksalsschatz" was simply made up for the show and doesn't actually exist in Germany or other German-speaking regions.
When Neil Patrick Harris directed a 2010 limited-run production of the musical "Rent" at the Hollywood Bowl, he cast Wayne Brady in the role of Tom Collins, after Brady and Harris had previously played brothers on "How I Met Your Mother".
Chris Romano, the actor who play Ted's childhood best friend "Punchy", is also a co-executive producer on the show.
Ted is from Ohio, just like Josh Radnor and Carter Bays. Bays and Ted share the same home town: Shaker Heights his character attends a Cleveland Browns themed wedding.
When both Samm Levine and Neil Patrick Harris were on Kevin Pollak's Chat Show (2009), Levine said that he was called to audition "more than once" for the role of Barney Stinson, even though he himself thought that he was wrong for the role. Levine told Harris that he thought Harris was better as Barney than he would have been.
In the episode "Little Minnesota", while Robin is telling the story about the NFC championship you can see a woman wearing a jersey that says "Smulders" on the back. Robin is played by Cobie Smulders.
Dave Coulier (Joey on Full House) made a cameo in an episode on Season 8 where he recites his famous "Cut It Out" line to which Bob Saget (Future Ted Narrator & Co-star alongside Coulier as Danny on Full House) narrators that part as "I always liked that joke."
Lily is the only character that had an onscreen kiss scene with all other 4 lead characters of HIMYM.
In the first two seasons, there is another room next to the clone trooper in Barney's apartment. From season three, there is just a wall next to the Stormtrooper.
The most viewed episode of the series is "The Pineapple Incident" from season 1 and the least viewed episode is "Landmarks" from season 6.
Ted always wanted kids and Robin didn't, when in reality Cobie Smulders has two children and Josh Radnor has none.
Neil Patrick Harris and Cobie Smulders would go on to co-star in A Series of Unfortunate Events (TV Series 2017-)
Lyndsy Fonseca, who plays Ted's daughter, is only four years younger than Cobie Smulders, who plays Ted's frequent love interest and friend, Robin.
The mother of co-creator Carter Bays is an ordained minister. Bays said he would only get calls from her if one or more jokes were not funny, despite the show's sometimes-risqué material.
All apartments the gang have lived in have featured a Chinese Checkers board as art on their wall. Ted and Marshall's apartment for example was by the bathroom.
Suit up! Is Barney's famous catch phrase and during the entire 9 seasons there are only 18 times when Barney doesn't suit up.
The Royal Diner that can be seen in the background of some street episodes is the same as the one seen on the show "Bones". Which coincident Alyson Hannigan and David Boreanaz co-starred together on Buffy the Vampire Slayer.
Series creators Craig Thomas and Carter Bays revealed that Scott Foley turned down the role of Ted Mosby and Jennifer Love Hewitt turned down the role of Robin Scherbatsky to star on Ghost Whisperer (2005).
In Season 9, Episode 18, the origin of where the nickname "Big Fudge" is finally revealed.
Barney's brother James was gay and married Tom and had 2 kids, a boy and a girl, it was related to Neil Patrick Harris and David Burtka, got married and had 2 kids, a boy and a girl
According to the Season 1 episode "Zip, zip, zip" Ted, Marshall and Lily's apartment is located at "75th and Amsterdam [Avenue]".
Four people in Marshall's family have names that start with Mar: Marshall's brothers Marcus and Marvin jr, Marshall's dad Marvin, and Marshall himself. This does not include Marcus' children, whose names all also start with "Mar".
3 Breaking Bad actors have appeared in the series as guests: Bryan Cranston (Walter White), Bob Odenkirk (Saul Goodman), and Matt Jones (Badger)
In Season 6, Marshall and Robin have never hung out alone. However, in an earlier season, Marshall and Robin went to a Minnesota and Canadian bar together several nights in a row.
We learn that Ted dated/hooked up with 65 women before he met "the mother". We don't see all the women, but all 65 of them are mentioned or seen through out the show.
In the earlier episodes of HIMYM, Robin's father was played by Eric Braeden, who has also played the part of Victor Newman for literally decades on the daytime drama, "The Young and the Restless." Then, in the later episodes of HIMYM, Robin's father was played by Ray Wise, who has for many years played the part of Ian Ward, one of Victor Newman's main antagonists on "The Young and the Restless."
Barney's magic number is 83. He uses it for most statistics. One time, in his old man make-up, he used it as his age.
In the episode stuff when the gang is at Barney's terrible play that he wrote to get revenge on Lily there is a flyer in the background that says "suck it Lily"
In season 4 while they are debating if Ted should be in a fight, on the wall behind Marshall a sign reads 'on this site in 1897 nothing happened'.
Guest stars Ashley Benson and Lucy Hale both have main roles on Pretty Little Liars (2010).
Unlike her gun-loving character Robin, in real life guns make Cobie Smulders uncomfortable.
Each member of the main group has had a failed engagement. Marshall and Lily with each other, Ted and Stella, Robin and Kevin, and Barney and Quin.
Many SNL cast members have appeared on the show including Chris Elliot, Abby Elliot, Will Forte, Martin Short, Jerry Minor, Chris Kattan, Taran Killam, Casey Wilson, Paul Shaffer, and Bob Odenkirk (writer, but appeared in sketches)
David Henrie (the son), Lucy Hale (Robin's sister) and Brian Kubach (Robin's first) all had a role in the Disney channel show Wizards of Waverly Place
Ted's favorite movie is Star Wars and he also loves the movie Annie Hall. Both movies were up against each other for best picture in 1978 and Annie Hall won.
Jason Segel was cast for the role of Marshall Eriksen because of his work on the short lived television show Freaks and Geeks (1999), of which HIMYM creators Carter Bays and Craig Thomas were huge fans. Besides Segel, other three actors from the "Freaks and Geeks" cast appeared on the show. Samm Levine played Phil on season 1 episode 5, "Okay Awesome", Martin Starr played Kevin on season 1 episode 8, "The Duel", and Busy Philipps played Rachel on season 3 episode 3, "Third Wheel".
Jennifer Morrison, JoAnna Garcia Swisher and Amy Acker have all appeared on "Once Upon A Time".
Jennifer Morrison (Ted's girlfriend Zoey in season 6), Anne Dudek (Ted's girlfriend in season 1) and Kal Penn (Robin's ex-boyfriend Kevin in season 7) also had starting roles in another show, "House, M.D.", as Cameron, Amber and Kutner, respectivelly
Alyson Hannigan's character on Buffy the Vampire Slayer (1996), Willow Rosenberg, once mentioned that she wrote Doogie Howser, M.D. (1989) fan-fiction as a girl. Hannigan went on to star in "How I Met Your Mother" with Neil Patrick Harris, who as a boy played Doogie Howser. Alyson Hannigan' who plays Lily, is perhaps best known prior to starring in 'How I Met Your Mother' for her role on "Buffy the Vampire Slayer". The creators of both of these shows - Joss Whedon of the Buffy series and Carter Bays and Craig Thomas of HIMYM - all graduated from Wesleyan University, as well as did the characters Lily, Ted, and Marshall on HIMYM. Additionally, Hannigan's character from the Buffy series, Willow, got early acceptance to Wesleyan, along with many other schools. Several cast members have also worked with Joss Whedon, notably stars Alyson Hannigan' (Buffy the Vampire Slayer), Neil Patrick Harris (Dr. Horrible's Sing-Along Blog) and Cobie Smulders (The Avengers). Also appearing have been guest stars Morena Baccarin (Firefly/Serenity), Alexis Denisof (Buffy the Vampire Slayer/Angel/Dollhouse), Amy Acker (Angel/Dollhouse), Tom Lenk (Buffy the Vampire Slayer/Angel), Harry Groener (Buffy the Vampire Slayer), Danny Strong (Buffy the Vampire Slayer). The search for all the main characters' so-called "doppelgangers" is a running joke throughout this series. In 'Buffy the Vampire Slayer' doppelgangers were also a frequent theme of many episodes, and most of the major characters (including Buffy, Xander, and Willow) encountered doubles of themselves through plot contrivances of magic or alternate universes.
In S4E23 "As Fast As She Can", Barney is trying to talk his way out of a traffic ticket. In S2E17 "Arrivederci, Fiero" it is revealed that Barney has a fear of driving. Thus giving the impression that he has learned how to drive, and his issues with buying a car in New York.
Zoey is the only guest star to appear in half the episodes of a given season (in her case season 6, when she appeared in 12/24 episodes)
In one episode, Robin deletes a contact from her phone, the camera captures the next name in her phone, "Dan Blocker". Dan Blocker is the deceased actor that played " Hoss Cartwright" on the TV series "Bonanza".
Three main members of the cast of Dawson's Creek (1998) guest starred on the show: Katie Holmes was Slutty Pumpkin / Naomi in "The Slutty Pumpkin Returns", James Van Der Beek was Robin's ex Simon Tremblay in three episodes and Busy Philipps was Rachel in "Third Wheel".
One ongoing joke is that a favorite topic is "Who is Ted's 'best friend'". Even though it is already confirmed that it is Marshall, Barney ignores this every time and claims that he is Ted's best friend.
Is season 6 episode 4 (Subway Wars) Ted points out the Arcadian Hotel to the bus driver. The next episode (Architect of Destruction) is where he finds out that is the spot of the new GNB headquarters and it will be torn down.
When Robin and Marshall go into the Little Minnesota bar, a woman is seen wearing a Minneosta Vikings jersey that has the last name Smulders on it. This also refers to Cobie Smulders who plays the character of Robin.
Ashley Benson and Lucy Hale, who played Barney's half-sister and Robin's sister, both starred in Pretty Little Liars.
In season 8 episodes 11 & 12 the new GNB building opens up, however they never seem to move into the building. All episodes after that with scenes at GNB still show Barney is his same office.
In the S01E14 "Zip, Zip, Zip" is claimed that Lily and Marshall wouldn't have peed in front of each other, although in S01E06 "Slutty Pumpkin" Marshall helps Lily pee.
If you watch throughout the episodes, you can see Robin, Lily, and Stella wearing the same necklaces on different characters. Also, at the end of S3 E20 "Miracles", the woman at the bar has the EXACT same purse as the woman in the opening scene of S4E1 "Do I Know You?"
On the Still Buffering podcast, HIMYM guest star Lin-Manuel Miranda mentioned that Rebecca Alson-Milkman (co-creator Craig Thomas's wife and the inspiration for Lily Aldrin) was a friend of his in high school theatre in NYC. They stayed pen pals when she went off to Wesleyan, then Miranda attended the same college where he reconnected and watched her and Thomas's romance begin.